(DRAFT) - Taxonomy
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
TAXONOMY
NAME - clam, California jackknife
OTHER COMMON NAMES - California short razor, short razor clam, jackknife clam and razor clam
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - Mollusca,
CLASS AND SUBCLASS - Bivalvia,
ORDER AND SUBORDER - Veneroida,
FAMILY AND SUBFAMILY - Psammobiidae,
GENUS AND SUBGENUS - Tagelus,
SPECIES AND SSP - californianus,
SCIENTIFIC NAME - Tagelus californianus
AUTHORITY -
TAXONOMY REFERENCES - 01
Taxonomy - 1 (DRAFT) - Status
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
STATUS
Coded Status
Commercial
Commercial/bait
See Comments
REFERENCES FOR STATUS - 01
COMMENTS ON STATUS -
Commercial:
This sepcies is commercially dug for use as fish bait. Harvest began in
1962 and during the mid-1970s harvests averaged about 6 t/year *01*.
Recreational:
Although edible, it is most often used as fish bait *01*.
Ecological:The California jackknife clam is a numerically important bivalve
species in southern California bays and lagoons *01*.
Status - 1 (DRAFT) - Distribution
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
LAND USE -
Water
Bays and Estuaries
REFERENCES FOR LAND USE - 01
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Estuarine 2
Marine 2
Estuarine 5
Marine 5
Estuarine, intertidal FL2
Estuarine, intertidal FL2
Estuarine, intertidal FL3
Estuarine, intertidal FL3
Marine, subtidal L
Marine, subtidal L
REFERENCES FOR NWI - 01
COMMENTS ON HABITAT ASSOCIATIONS -
HABITAT TYPE:
Eggs and larvae are estuarine-neritic. Adults and juveniles are common
near mean low tide where sediments are appropriate. Adults and juveniles
inhabit sand, mud, or muddy sand flats near the low tide level in bays,
sloughs, and estuaries. This species reportedly occurs from +0.2 to -0.5m
mean tide level, but does not occur above mean sea level in San Diego Bay.
The bays and lagoons this species inhabits are euhaline on an annual basis.
In low intertidal substrates, it is commonly associated with the rosy
jackknife (Solen rosaceus) *01*.
SUBSTRATE:
The California jackknife clam prefers sediments having some silts and clays
(2-15%), and cannot burrow into sediments that are composed primarily of
sand *01*.
PHYSICAL/CHEMICAL CHARACTERISTICS:
This species is found in mesohaline-euhaline waters where water
temperatures range from 9 to 30 degrees C. Temperatures equal to or greater
than 35 degrees C cause adult mortalitiy. In San Diego Bay, the clam's
upper lethal tolerance limit (LT50) was 35.5 degrees C in December and 37.6
degrees C in May. Smaller sizes (23-46 mm) are more resistant to elevated
temperatures *01*.
ANIMAL/PLANT SPECIES ASSOCIATIONS -
rosy jackknife (Solen rosaceus)
planktivorous fishes
invertebrates
diamond turbot
stingrays (Dasyatis spp.)
stilts (Himantopus spp.)
godwits (Limosa spp.)
curlews (Numenius spp.)
dowitchers (Limnodromus spp.)
REFERENCES FOR SPECIES ASSOCIATIONS - 01
Habitat Associations - 1 COMMENTS ON SPECIES ASSOCIATIONS -
In low intertidal substrates, it is commonly associated with the rosy
jackknife (Solen rosaceus) *01*.
Predation: Larvae probably are eaten by planktivorous fishes and
invertebrates. Newly-settled individuals and juveniles are eaten by
numerous fishes, including diamond turbot (Hypsopsetta guttulata), stingrays
(Dasyatis spp.) and other rays. Birds such as stilts (Himantopus spp.),
godwits (Limosa spp.), curlews (Numenius spp.), and dowitchers (Limnodromus
spp.), also prey on the California jackknife clam *01*.
Habitat Associations - 2 (DRAFT) - Food Habits
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
FILTERER
REFERENCES FOR TROPHIC LEVEL - 01
LIFESTAGE FOOD FOOD PART
General Algae Not Applicable
General Microorganisms Not Applicable
General Phytoplankton Not Applicable
General Plankton Not Applicable
General Bacillariophyceae Not Applicable
General Detritus Not Applicable
REFERENCES FOR GENERAL FOOD - 01
COMMENTS ON FOOD -
The California jackknife clam is a suspension feeder, although originally it
was thought to be a deposit feeder. When feeding, it is located about 10 cm
below the substratum surface and extends its two diphons into the water
through separate openings. The siphon openings lay at the sediment-water
interface *01*.
The California jackknife clam feeds on phytoplankton, probably including
diatoms, dinoflagellates, and other types of phytoplankton. Its diet may
include suspended detrital particles and their associated epifauna *01*.
Food Habits - 1 (DRAFT) - Environment Associations
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Temperature: Greater than 27 degrees C
G Water Temperature: Between 21-27 degrees C
G Water Temperature: Between 15-21 degrees C
G Water Temperature: Below 15 degrees C
G Water Temperature: Specified in Comments
LIM Water Temperature: Specified in Comments
G
A Substrate: Mud or silt
J Substrate: Mud or silt
A Substrate: Sand
J Substrate: Sand
J Substrate: Specified in Comments
A Substrate: Specified in Comments
A Relation to Substrate: Occurs in substrate [penetrating]
J Relation to Substrate: Occurs in substrate [penetrating]
A Relation to Substrate: Specified in Comments
J Relation to Substrate: Specified in Comments
A Bottom Type [Aquatic]: Mud or silt
J Bottom Type [Aquatic]: Mud or silt
A Bottom Type [Aquatic]: Sand
J Bottom Type [Aquatic]: Sand
A Bottom Type [Aquatic]: Specified in Comments
J Bottom Type [Aquatic]: Specified in Comments
G Aquatic Habitat Zonation: Specified in Comments
A Soil Depth: Specified in Comments
J Soil Depth: Specified in Comments
A Coastal Features: Mudflats
J Coastal Features: Mudflats
A Coastal Features: Specified in Comments
J Coastal Features: Specified in Comments
G Coastal Wetlands: Sounds and bays
G Coastal Wetlands: Specified in Comments
G Estuarine habitat zone: bay
G Estuarine habitat zone: sound
G Estuarine habitat zone: specified in comments
E Currents: tidal
E Currents: specified in comments
L Currents: tidal
L Currents: specified in comments
Environment Associations - 1 (DRAFT) - Environment Associations
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 01
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 01
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 01
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 01
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
High temperature (e.g., thermal effluent from power plants) can adversely
affect populations *01*.
HABITAT TYPE:
Eggs and larvae are estuarine-neritic. Adults and juveniles are common
near mean low tide where sediments are appropriate. Adults and juveniles
inhabit sand, mud, or muddy sand flats near the low tide level in bays,
sloughs, and estuaries. This species reportedly occurs from +0.2 to -0.5m
mean tide level, but does not occur above mean sea level in San Diego Bay.
The bays and lagoons this species inhabits are euhaline on an annual basis.
In low intertidal substrates, it is commonly associated with the rosy
jackknife (Solen rosaceus) *01*.
SUBSTRATE:
The California jackknife clam prefers sediments having some silts and clays
(2-15%), and cannot burrow into sediments that are composed primarily of
sand *01*.
PHYSICAL/CHEMICAL CHARACTERISTICS:
This species is found in mesohaline-euhaline waters where water
temperatures range from 9 to 30 degrees C. Temperatures equal to or greater
than 35 degrees C cause adult mortalitiy. In San Diego Bay, the clam's
upper lethal tolerance limit (LT50) was 35.5 degrees C in December and 37.6
degrees C in May. Smaller sizes (23-46 mm) are more resistant to elevated
temperatures *01*.
COMMENTS ON LIMITING ENVIRONMENTAL ASSOC_ -
High temperature (e.g., thermal effluent from power plants) can adversely
affect populations *01*.
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Adults and juveniles are common near mean low tide where sediments are
appropriate. Adults and juveniles inhabit sand, mud, or muddy sand flats
near the low tide level in bays, sloughs, and estuaries. This species
reportedly occurs from +0.2 to -0.5m mean tide level *01*.
COMMENTS ON JUVENILE ENVIRONMENTAL ASSOC_ -
Adults and juveniles are common near mean low tide where sediments are
appropriate. Adults and juveniles inhabit sand, mud, or muddy sand flats
near the low tide level in bays, sloughs, and estuaries. This species
reportedly occurs from +0.2 to -0.5m mean tide level *01*.
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Eggs and larvae are planktonic, and estuarine-neritic *01*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Eggs and larvae are planktonic, and estuarine-neritic *01*.
Environment Associations - 2 (DRAFT) - Life History
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
LIFE HISTORY
PHYSICAL DESCRIPTIONS:
Juvenile size range: The stout tagelus (Tagelus plebius) is a congener, and
has spat that settle out of the water column at 155-175 um in shell length
(SL). Clams average about 46mm SL at 2.5 years *01*.
Age and size of adults: The California jackknife reaches maturity between 60
and 120 mm SL. Age and growth of this species has not been determined, but
it appears to reach reproductive size in 2-3 years. Ultimate age is
unknown. Clams in San Diego Bay average 72 mm SL and appear to be 5 years
old *01*.
REPRODUCTION: This species is gonochoristic, oviparous, and iteroparous. It
is a broadcast spawner; eggs are fertilized externally *01*.
The exact spawning time for this species is unknown, however, spawning
occurs intertidally during high tide. Eggs and sperm are released through
the exhalant siphon. Based on the settlement of young, a peak spawning
probably occurs in early spring (May-June recruitment), with some spawning
occuring year-round *01*.
Embryonic development is probably indirect and external *01*.
BEHAVIOR: Eggs and larvae are dispersed by currents. Juveniles and adults
migrate up and down in their burrow as the tide rises and falls and will
rapidly descend in their burrows when disturbed *01*.
Eggs and larvae are planktonic. Juveniles and adults are benthic infauna of
bays, estuaries, or lagoons. Juveniles and adults live in a permanent,
nonmucous-lined vertical burrow 10-50 cm deep in which they can readily
move up and down *01*.
PREDATION: Larvae probably are eaten by planktivorous fishes and
invertebrates. Newly-settled individuals and juveniles are eaten by
numerous fishes, including diamond turbot (Hypsopsetta guttulata), stingrays
(Dasyatis spp.) and other rays. Birds such as stilts (Himantopus spp.),
godwits (Limosa spp.), curlews (Numenius spp.), and dowitchers (Limnodromus
spp.), also prey on the California jackknife clam *01*.
LIFE HISTORY CODES -
Foraging Strategy: Filtering
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Nest/Den Site: Underwater burrow
Spawning Site: Flowing Water
REFERENCES FOR LIFE HISTORY- 01
Life History - 1 (DRAFT) - Management Practices
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial
Beneficial Controlling pollution [thermal, chemical, physical]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 01
COMMENTS ON MANAGEMENT PRACTICES -
High temperature (e.g., thermal effluent from power plants) can adversely
affect populations *01*.
FACTORS INFLUENCING POPULATIONS:
Population densities are influenced by tidal elevation, water temperature,
sediment characteristics, recruitment, and mortality. There are no
indications that populations are controlled by density-dependent
interactions *01*.
Management Practices - 1 (DRAFT) - References
Species clam, California jackknife
Species Id M060131
Date 26 AUG 96
References
01 * Emmett, R.L., S.L. Stone, S.A. Hinton, and M.E. Monaco. 1991.
Distribution and abundance of fishes and invertebrates in west coast
estuaries, Volume II: species life history summaries. ELMR Rep.No.8
NOAA/NOS Strategic Environmental Assessments Division, Rockville, MD. 329
pp.
References - 1